Torque and position sensing systems are vital for electrical power steering systems in automobiles, among other applications. When a driver steers an automobile, electrical power steering systems may add energy during zero to low speeds when higher torque is required to adequately steer. Power steering systems may also provide feedback force to the driver during high speeds when less torque is required, ensuring that drivers are aware of the forces acting on the front wheel. Detecting the torque and position on the steering column is important to determine how much energy the power steering system should apply to aid the driver in steering.
Prior methods for measuring torque may involve a torsion bar that twists with the amount of force applied to the steering column and a sensor that measures the amount of twisting occurring on the torsion bar. A separate mechanism for measuring angular position may involve a circular resistive tracking circuit with known linear resistance and a positive voltage applied to one end of the track. Voltage may be measured at an output contact moving with the shaft's rotation along the resistive track. The change in voltage may signify the shaft's position. Both of these methods may be expensive to assemble and maintain, and may enlarge the size of the steering column and power steering system.